An oil spill in the Mystic River has been traced to a ruptured fuel line that dumped more than 1,000 gallons of petroleum into surface waters near a Chelsea oil depot, state officials said yesterday.

Authorities said the spill at Global Oil Co. forced clean-up crews to spend a second day trying to contain petroleum in the river and prevent it from causing environmental damage.

“We’ve gotten the majority of it out of the water,” said Joe Ferson, a spokesman for the Department of Environmental Protection. “But it is still an ongoing situation.”

Ferson said clean-up crews removed 1,000 gallons of fuel from the river and siphoned another 5,000 gallons of fuel and water. He said the leak was traced to a ruptured fuel line on Global Oil’s Broadway Street property.

Authorities have been working to clean up the spill since being notified of the problem Monday morning. Coast Guard officials and the Chelsea Fire Department have been monitoring the fuel closely to prevent damage to wildlife.

Officials with Global Oil could not be reached for comment yesterday.

Ferson said it is too early to determine whether Global Oil would face fines as a result of the spill, but he said the company took immediate steps to contain the damage and has been cooperative with efforts to isolate the source.